> I'm using the EMERGE_DEFAULT_OPTS="--keep-going"
> portage option to ignore missing files. This is enough for me.

Not for me. I had tried the world update this night, but after a few
packages (kde-env being the only KDE4-one) it failed to download oxygen-
icons, and was unable to resume. Some of the packages that have updates
pending are ffmpeg or glib, I don't understand why missing KDE4 stuff
prevents their update.
Wonko